tests: Add headless native backend test

It doesn't do anything more than construct and tear down, but it's a
start.

Don't run the test as part of CI yet, as doesn't have the DRM devices
needed.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1698>

.gitlab-ci.yml

@@ -191,7 +191,7 @@ build-fedora-container@aarch64:
     - .fdo.distribution-image@fedora
   stage: build
   script:
-    - meson . build -Dbuildtype=debugoptimized -Db_coverage=true -Degl_device=true -Dwayland_eglstream=true --werror --prefix /usr
+    - meson . build -Dbuildtype=debugoptimized -Db_coverage=true -Degl_device=true -Dwayland_eglstream=true -Dnative_tests=false --werror --prefix /usr
     - ninja -C build
     - ninja -C build install
   artifacts:
@@ -221,7 +221,7 @@ build-without-opengl-and-glx@x86_64:
   needs:
     - build-fedora-container@x86_64
   script:
-    - meson . build -Dbuildtype=debugoptimized -Dopengl=false -Dglx=false -Degl_device=true -Dwayland_eglstream=true --werror --prefix /usr
+    - meson . build -Dbuildtype=debugoptimized -Dopengl=false -Dglx=false -Degl_device=true -Dwayland_eglstream=true -Dnative_tests=false --werror --prefix /usr
     - ninja -C build
     - ninja -C build install
   artifacts:
@@ -236,7 +236,7 @@ build-without-native-backend-and-wayland@x86_64:
   needs:
     - build-fedora-container@x86_64
   script:
-    - meson . build -Dbuildtype=debugoptimized -Dnative_backend=false -Dudev=false -Dwayland=false -Dcore_tests=false --werror --prefix /usr
+    - meson . build -Dbuildtype=debugoptimized -Dnative_backend=false -Dudev=false -Dwayland=false -Dcore_tests=false -Dnative_tests=false --werror --prefix /usr
     - ninja -C build
     - ninja -C build install
   artifacts:

meson.build

@@ -262,6 +262,7 @@ have_tests = get_option('tests')
 have_core_tests = false
 have_cogl_tests = false
 have_clutter_tests = false
+have_native_tests = false
 have_installed_tests = false
 
 if have_tests
@@ -271,6 +272,12 @@ if have_tests
       error('Tests require Wayland to be enabled')
     endif
   endif
+  have_native_tests = get_option('native_tests')
+  if have_native_tests
+    if not have_native_backend
+      error('Native tests require the native backend')
+    endif
+  endif
 
   have_cogl_tests = get_option('cogl_tests')
   have_clutter_tests = get_option('clutter_tests')

meson_options.txt

@@ -117,6 +117,12 @@ option('core_tests',
   description: 'Enable mutter core tests'
 )
 
+option('native_tests',
+  type: 'boolean',
+  value: true,
+  description: 'Enable mutter native backend tests'
+)
+
 option('tests',
   type: 'boolean',
   value: true,

src/backends/native/meta-backend-native.h

@@ -32,6 +32,7 @@
 #include "backends/native/meta-udev.h"
 
 #define META_TYPE_BACKEND_NATIVE (meta_backend_native_get_type ())
+META_EXPORT_TEST
 G_DECLARE_FINAL_TYPE (MetaBackendNative, meta_backend_native,
                       META, BACKEND_NATIVE, MetaBackend)
 

src/tests/meson.build

@@ -157,6 +157,21 @@ anonymous_file_test = executable('anonymous-file-tests',
   install_dir: mutter_installed_tests_libexecdir,
 )
 
+if have_native_tests
+  native_headless_tests = executable('mutter-native-headless-tests',
+    sources: [
+      'native-headless.c',
+      'test-utils.c',
+      'test-utils.h',
+    ],
+    include_directories: tests_includepath,
+    c_args: tests_c_args,
+    dependencies: [tests_deps],
+    install: have_installed_tests,
+    install_dir: mutter_installed_tests_libexecdir,
+  )
+endif
+
 stacking_tests = [
   'basic-x11',
   'basic-wayland',
@@ -223,3 +238,12 @@ test('anonymous-file', anonymous_file_test,
   is_parallel: false,
   timeout: 60,
 )
+
+if have_native_tests
+  test('native-headless', native_headless_tests,
+    suite: ['core', 'mutter/native/headless'],
+    env: test_env,
+    is_parallel: false,
+    timeout: 60,
+  )
+endif

src/tests/native-headless.c

@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2021 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ */
+
+#include "config.h"
+
+#include "backends/meta-settings-private.h"
+#include "backends/native/meta-backend-native.h"
+#include "compositor/meta-plugin-manager.h"
+#include "core/main-private.h"
+#include "meta/main.h"
+#include "meta/meta-backend.h"
+#include "tests/test-utils.h"
+
+static void
+init_tests (void)
+{
+}
+
+static gboolean
+run_tests (gpointer data)
+{
+  MetaBackend *backend = meta_get_backend ();
+  MetaSettings *settings = meta_backend_get_settings (backend);
+  gboolean ret;
+
+  meta_settings_override_experimental_features (settings);
+  meta_settings_enable_experimental_feature (
+    settings,
+    META_EXPERIMENTAL_FEATURE_SCALE_MONITOR_FRAMEBUFFER);
+
+  ret = g_test_run ();
+
+  meta_quit (ret != 0);
+
+  return FALSE;
+}
+
+int
+main (int    argc,
+      char **argv)
+{
+  test_init (&argc, &argv);
+  init_tests ();
+
+  meta_plugin_manager_load (test_get_plugin_name ());
+
+  meta_override_compositor_configuration (META_COMPOSITOR_TYPE_WAYLAND,
+                                          META_TYPE_BACKEND_NATIVE,
+                                          "headless", TRUE,
+                                          NULL);
+
+  meta_init ();
+  meta_register_with_session ();
+
+  g_idle_add (run_tests, NULL);
+
+  return meta_run ();
+}